Commutator for electric machines



g- 4, 1959 R. H. BOYER 2,898,488

COMMUTATOR FOR ELECTRIC MACHINES Filed Dec. s, 1956 2 Sheets-S1196. 1

JNVENTOR. @0552 T H 50 5 52 ATTY Aug. 4, 1959 R. H. BOVYER COMMUTATOR FOR ELECTRIC MACHINES 2 Sheets-Sheet 2 Filed Dec. 5, 1956 I II (I 7 J a INVENTOR. Aoazeer H 50 ea AvTvks.

United States PatentOfifice Fatented Aug. 4, 1959 COMMUTATOR non ELECTRIC MACHINES Robert H. Boyer, Cleveland, Ohio, assignor to The Kirkwood Commutator Company, Cleveland, Ohio, a corporation of Ohio Application December 5, 1956, Serial No. 626,502

7 Claims. (Cl. 310-236) This invention relates to commutators, especially to commutators for rotary types of electrical apparatus.

Heretofore there have been many different types of commutators provided for different rotating electrical machines, but one style of commutators that have been particularly diifcult to build in the past are those having relatively long axial lengths. Some of such commutators have had special exteriorly positioned shrink rings placed around the center peripheral portions of the commutator, or they have been otherwise reenforced in order to pre vent such center portions of the commutators from working loose, or bulging outwardly under load. It will be noted that relatively high centrifugal loads are applied to commutators in many instances and with long axial commutators, these loads have been sufficient to cause failure of the commutator in many instances. Obviously any special reenforcing rings are costly and interfere with the use of the commutator in some instances.

In general, it has been difiicult and relatively expensive to produce long axial length commutators as these commutators usually have had more parts in them than similar commutators, and they have been complex to build and limited in service.

The general object of the present invention is to pro vide a new and improved type of a commutator of the class described and characterized by the provision of a plurality of internal tangs or similar member for securing a commutator segment to a commutator carrier shaft means.

Another object of the invention is to provide a commutator design particularly adapted for use in building relatively long axial length commutators and to have a sturdy construction particularly effective for resisting centrifugal forces exerted on the commutator and its segments.

Another object of the invention is to provide an improved type of a commutator building method by which a novel internal holding action can be secured on commutator segments.

Yet a further object of the invention is to' provide a commutator segment that has a plurality of internal tangs thereon which are effectively secured to commutator shaft means for positioning action.

The foregoing and other objects and advantages of the invention will be made more apparent as the specification proceeds.

For a better understanding of the present invention, reference should now be had to the accompanying drawings, wherein:

Fig. 1 is a longitudinal vertical section through a commutator carrier sleeve which is the starting member in the method of producing the novel commutator of the invention;

Fig. 2 is a section, similar to Fig. 1, showing the operation of positioning an internal holding ring and insulation means on the commutator sleeve;

Fig. 3 is a section, similar to the other figures of the drawings, indicating the step of positioning of a plurality of commutator and insulation segments in engagement With the holding means provided in the center portion of the commutator shaft assembly;

Fig. 4 is a longitudinal vertical section through a completed commutator embodying the principles of the invention;

Fig. 5 is a fragmentary left end view of the commutator of Fig. 4;

Fig. 6 is a section, like Fig. 2, of a modification of the invention; and

Fig. 7 is a fragmentary elevation of a commutator cooling segment of the invention.

When referring to corresponding parts shown in the drawings and referred to in the specification, corresponding numerals are used for facilitating comparison therebetween.

The present invention, generally speaking, relates to a commutator including a center shaft or sleeve means having a projecting means on the periphery thereof, an internal tang securing ring having a laterally overhanging side portion thereon, which tang securing ring is carried on the center shaft means and has its other side abutting against the projecting means on the center shaft means or unit, a plurality of commutator segments each of which has a pair of axially spaced, radially inwardly extending tangs thereon at least one of which has dovetailed edges and engages the overhanging side portions of the tang securing ring; and the commutator is completed by means engaging the axially outer edges of the tangs on the commutator segments and securing them to the center shaft means to position the commutator segments around the periphery of such shaft means.

Attention now is particularly directed to the details of the invention as best shown in the drawings, and a commutator 1 of the invention is shown in Figs. 4 and 5 of the drawings, while the other figures show the steps in the production, or manufacture of such commutator 1.

Fig. 1 of the drawings illustrates that some siutable shaft member, such as a metal carrier or center sleeve 2 is provided as a center support for the commutator. Such sleeve 2', as an important feature thereof, has some type of axially outwardly extending or protruding means, for example, a shoulder 3 provided thereon. This sleeve 3 has threaded end portions, as indicated at 4 for a purpose to be hereinafter described in detail.

In order to provide the desired internal securing action for connnutator segments in the commutator 1, an internal tang securing ring 5 is positioned over the sleeve 2 and it may have a shoulder 6 thereon that snugly engages the outer end of the shoulder 3 to aid in securing the internal tang securing ring 5 in a desired accurate and fixed position on the periphery of the sleeve 2. Preferably some type of a laterally protruding, or overhanging side 7 is provided on the opposite lateral margin of the internal tang securing ring 5. Any suitable strips, bands or pieces of insulation means 8, 8 next are placed over the periphery of the sleeve 2 after shaped pieces of insulation 9, 9 are placed over the internal tank securing ring 6, as shown in Fig. 2. The insulation pieces are abutted at their ends to cover the bushing 2 and the members thereon.

Next the individual commutator segments 10 are positioned or brought into engagement with the internal tang securing ring 6 around the peripheries of such internal tang securing ring and the sleeve 2. Suitable insulation segments are positioned intermediate the commutator segments as they are assembled. The commutator segments 10 and insulation segments 100 preferably are each provided with a pair of tangs 11 and 12 adapted to extend radially inwardly of the commutator segments 10 as positioned in the commutator 1. It will be seen that the tang 11 is of dove tailed shape and with one of such overhanging side edges 13 being shaped, in general, complementary to the overhanging side edge 7 of the internal tang scouring ring so that an effective engagement or securing action is supplied for each of the commutator segments 10 axially intermediate the ends thereof. Also, the tang 12 has one overhanging side edge 14 provided thereon which, with the other edge of the tang 11 exposed at the end of the commutator, is adapted to engage with anchor rings 15 and 16, respectively. Suitable pieces of insulation 17 are positioned intermediate the anchor rings 15 and 16 and the associated portions of the commutator segments, as is conventional in commutator construction, so that proper electrical action can be provided by the commutator.

The commutator 1 is completed by means of a pair of end or lock rings 18 that engage the threaded Zones or sections 5 on the bushing 3 for locking the anchor rings 15 and 16 in position. Portions on these anchor rings 15 and 16 are formed complementary to the overhanging edges of the commutator segments for completing the locking or positioning action on such segments.

Each of the commutator segments 10 normally has an end riser 19 provided thereon for suitable connection of armature leads thereto, but the leads may be secured to the segments in any desired manner.

Several special commutator segments 10a, in the construction shown, have cooling grooves 30 provided therein. This cooling groove in each segment 19a extends the length of the commutator segment radially outwardly of the end rings 15 and 16, and it permits air to circulate axially of the commutator and within the commutator. The groove 30 can be of any desired shape in section and as many as desired of the commutator segments 10 can be provided with one or more cooling grooves therein.

One main feature of the structure shown in Fig. 6 of the drawings relates to a novel carrier sleeve 50 which is provided for this commutator of the invention. As an important feature of the sleeve 58, it has an integral annular shoulder or rib 51 provided thereon extending generally radially thereof but wherein at least one of the lateral margins of this shoulder or rib 51 has an overhanging side edge 52 provided thereon. This overhanging lateral edge 52 of the rib 51 is adapted to be engaged with the complementary shaped tang or suitable other lug member provided on the commutator segment 53 used in this commutator. Thus a simplification of the assembly of the commutator and the carrier sleeve therefor has been provided.

It will be seen that a plurality of ribs, like the rib 51, can be provided upon a commutator center sleeve at axially spaced portions thereof, if desired. This construction would be particularly suitable for long eommutators and where commutator segments like the one 53 could be provided with a plurality of tangs thereon to engage with any desired number of integral retaining ribs or similar means provided upon the commutator carrier sleeve.

When more than one anchor or securing ring or rib would be provided by the carrier sleeve, it would be desirable to have these retaining rings fixedly secured to, or integral with the carrier sleeve, as it would facilitate assembly of the components of the commutator.

It should be realized that any desired type of means can be provided for exerting an axial compression force upon the commutator segments and commutator assembly in order to hold them in association with each other. Thus bolt and washer means could be used for extending axially of the commutator and engaging the end portions of the commutator segment and insulation members to secure them together, or a rivet could be used for such action, etc. as desired. It further will be realized that end rings, like the members 15 and 16 provided herein, can be varied as desired in any particular commutator construction.

Any desired complementary interengaging shapes can be provided on the tang securing means and the commutator tangs as long as such means retain the commutator segments against radially outward movement in the commutator.

It will be seen that the present invention provides a novel commutator segment shape and special means for cooperating with internal tangs on the commutator segments for retaining them in position against centrifugal forces and other forces exerted thereon tending to pull the commutator apart, or to throw off any of the commutator segments when the commutator 1 is in use.

This commutator 1 has been made by a novel, improved method, the steps of which can be easily followed in manufacturing procedures, and a novel, useful commutator has been provided. The commutator is particularly adapted to be built in relatively long axial lengths and to give effective service life under all conditions. Thus the objects of the invention have been achieved.

While several complete embodiments of the invention have been disclosed herein, it will be appreciated that modification of these particular embodiments of the invention may be resorted to without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

l. A commutator comprising a center sleeve having an annular projecting shoulder on the periphery thereof, an internal tang securing ring having a laterally overhanging side portion thereon, said tang securing ring being carried by said center sleeve and having a side abutting against said shoulder on said center sleeve, a plurality of commutator segments each of which has a pair of axially spaced radially inwardly extending tangs of the same length thereon, only one of said tangs on each said commutator segment having a dove tailed edge on a laterally inner end thereof and with said edge engaging said overhanging side portion of said tang securing ring, end rings engaging said tangs on said commutator segments and being secured to said center sleeve to position said commutator segments around the periphery of and to secure said commutator segments to said center sleeve; and insulation means intermediate adjacent ones of said commutator segments, and between said commutator segments and said center sleeve and said tang securing ring.

2. A commutator comprising a center shaft means having projecting means on the periphery thereof, an internal tang securing ring having a lateral overhanging side portion thereon, said tang securing ring being carried by said center shaft means and having one side abutting against said projecting means on said center shaft means, a plurality of commutator segments each of which has a pair of axially spaced radially inwardly extending tangs thereon, only one of said tangs on each said commutator segment having a dove tailed laterally inner edge thereon, said edge engaging said overhanging side portion of said tang securing ring, and means engaging said tangs on said commutator segments and said center shaft means to position said commutator segments around the periphery of said center shaft means.

3. In a commutator, a plurality of commutator segments having tangs thereon, a carrier sleeve for said commutator segments, and means securing said commutator segments to said carrier sleeve by engaging radially inner portions of the tangs of said commutator segments, said commutator segments extending axially of said carrier sleeve, at least one of said commutator segments having a cooling recess therein spaced from the radial margins of such segment and extending the length thereof radial outwardly of said tangs and open at both ends for passage of air therethrough.

4. A commutator as in claim 3 wherein said cooling recess is provided in a plurality of said commutator segments.

5. A commutator comprising a center member having an annular projecting shoulder on the periphery thereof and having only one laterally overhanging side portion thereon, a plurality of commutator segments each of which has a pair of axially spaced radially inwardly extending tangs thereon at radially equal length portions thereof, only one of said tangs on each said commutator segment having a dove tailed lateral edge engaging said overhanging side portion of said center member, end rings engaging said tangs on said commutator segments and secured to said center member to position said commutator segments around the periphery of said center member, and insulation means intermediate adjacent ones of said commutator segments and between said commutator segments and said center member.

6. A commutator comprising shaft means, internal tang securing means including only one laterally overhanging side portion thereon on said shaft means and secured against movement therealong, a plurality of commutator segments each of which has a pair of axially spaced radially inwardly extending tangs of substantially the same radial length thereon, only one of said tangs on each said commutator segment having an axially inner undercut edge section thereon and which engages said overhanging side portion of said tang securing means to be retained thereby against radially outward movement, and means opera- 6 tively engaging said shaft means and both tangs on said commutator segments to complete the commutator.

7. In a commutator, a carrier sleeve, a plurality of commutator segments each having several tangs thereon but with only one said tang thereon having an overhanging axially inner lateral edge, anchor ring means having a dovetail shaped lateral edge carried by said carrier sleeve and engaging said overhanging tang edge and preventing radially outward movement thereof, said commutator segments being of the same radial length at both of said tangs, and sleeve means engaging said carrier sleeve and the axially outer ends of both of said tangs to operatively position said anchor ring means in the commutator.

References Cited in the file of this patent UNITED STATES PATENTS 678,171 Geisenhoner July 9, 1901 891,316 Williamson June 23, 1908 970,233 Jeffrey Sept. 13, 1910 1,222,465 Priest Apr. 10, 1917 1,713,089 Phillips May 14, 1929 FOREIGN PATENTS 894,878 Germany Oct. 29, 1953 918,458 Germany Sept. 27, 1954 

